Convert from royal foot to pie [Spanish]

Unit Definition (royal foot)
The royal foot is a French pied de roi, also called the Paris foot in English.

Unit Definition (pie [Spanish])
The pie is a traditional foot of Spain. The pie equals 1/3 vara or 12 pulgadas. The pie used in Spain is about 27.86 centimeters or 10.97 inches, but in Spanish Latin America the pie is generally longer.